Herbicidal compositions



Patented Apr. '7, 1953 HERBICIDAL COMPOSITIONS David T. Mowry and Arthur H. Schlesinger, Dayton, Ohio, assignors to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware N Drawing. Application December 26,1951,

Serial No. 263,482

:The present invention provides new and highly valuable herbicidal compositions and methods of destroying or preventing plant growth in which said compositions are employed.

We have found that improved, very efficient herbicidal compositions are obtained when there are prepared oil-in-water emulsions of a ketone having the formula R COY Herbicidal compositions containing the present thianaphthenyl ketones are readily obtained by first preparing a" solution of the ketone in an organic solvent and then adding the resulting solution to water containing an emulsifying agent toform an emulsion. Because of the very high herbicidal efficiency of the ketone they are present in a herbicidal composition in only very small concentrations, for example, in concentrations ofu from 0.1 per cent to 2 per cent by Weight of the total weight of the emulsion. Emulsifying agents. Whichmay be employed are those customarily used in the art for the preparation of oil-:in-water emulsions. The word oil is here used to designate any liquid which is insoluble.

in water. Since the present ketones are highly stable compounds of little chemical reactivity, they are not affected by either ionic or nonionic emulsifying agents. Examples of emulsifying agents which may be usedinclude alkylbenzene- .sulfonates, long chained polyalkylene glycols,, long. chained succinate'syetcr Examples of organic solvents which may be used in preparing the emulsions include hydrocarbon liquids such as kerosene, hexane, benzene, and toluene, fatty oils, nitro compounds such as nitrobenzene or nitrobutane, chloro compounds such as carbon tetrachloridel f or I the chlorobenzenes, iketones .13 Claims. (01. 71-25) 2 such as cyclohexanone or methyl ethyl ketone,: etc. 7 v v 1 The present emulsions possess the property of destroying and/or preventing plant growth. When applied to broad-leafed crops, e. g-., beans, they possess a marked defoliant effect. Inasmuch as defoliants are of economic importance in that their use permits easy machine-harvesting or hand-picking of non-leafy crops, the leaf? drop effect of the present herbicides is of particularsignificance. The present emulsions may be used to destroy-already existing plant growth by direct application to the undesirable plants, e.g., by'spraying; or'the emulsions may be employed to prevent plant growth by application to media which normally support plant growth, When employed to prevent plantgrowth, iorexample in parking areas, highway abutments, railway yards, ,etc., the emulsions may be applied by spraying only the surface of said media or they maybe admixed with saidmedia. .Generally, spraying of only, the soil surface is sufficient to prevent plant growth in areas which are. to be kept clear of plants. However the emulsions may be incorporated into customarily employed temporary surfacing materials, e. g., oils, cinderS, etc. The present invention is further ;illustrated,

but not limited, by the following examples: 7

Example 1 Spray testing of the present herbicidal compositions was conducted asfollows:

A cyclohexanone solution of methyl 3 -thia naphthenyl. ketone and an emulsifying agent were added to water, the quantity of solution; employed being calculated to give emulsions containingLO per cent of the thianaphthenyl.

amixture of a polyalkyleneglycolderivative an an alkylbenzenesulfonate. V Three-week old corn and bean plants were sprayed with the emulsiontwo plants of each variety being employed. Thespraying was continued until droplets formed on and/or fell from the foliage and stems 'of'the sprayed plants, up

to 15 m1. of the emulsion being applied to, each,

Plan The Sprayed l h s e jastwqfnn' treated blank. :specimens' of i each plant were in order to determine the extent of injury, ii any.

The sprayed corn plants were found to be severely injured, with leaves dried. The sprayed bean plants were also severely injured. They were completely defoliated.

.Erample 2 Another method of testing for herbicidal efficiency of a chemical involves noting the efiects on seed germination and plant growth which'may be evidenced by spraying soil surfaces. This test, commonlyknown as a pre-emergence'tes was conducted as follows:

Boxes having a 5" x 5" exposed area were partially filled with a layer of soil and seeds were placed thereon and then covered with a $41" to /2" layer of soil which had been screened to A1" sieve. Test boxes containing 20 seeds each of beet and radish seeds, respectively, were prepared. The surface soil of the seeded boxes was then sprayed, respectively, with the -'-1.0 per cent emulsion of Example 1. The quantity of the emulsion whichwas*applied'wascalculated to correspond to -50lbssof the ketoneper acre. In the present'instance, 9.1 cc.-of the 1.0 per cent emulsion "per square "inches of surface soil was calculated tocorrespondto 50 lbsncf the chemical per acre. The sprayed boxes as well as similar seededbutnnsprayed 'boxes were' then maintained at'standard conditions of temperature and-watering for "zaiperic'd'of two weeks. At the end of that time'the number of healthy seedlings in each box was counted. 'Thus' the number 'of-non-em'erging and da-m'aged :seedli-ngs was obtained by difierence. This 'difierenc'e is designated-as"-X; Per cent phytot'oxicity was determined by the ratio of-X to the number of healthy seedlings in the controls. There was thus evidenced a phytotoxicityof from 71% to 100% to both test specimens.

While the present ketones are most advantageously employed as herbicides .by incorporating them into an emulsion as herein described, they may also be employed in other plant destroying methods. Thus they may be incorporate into solid carriersusuch as -clay, talc, pumice and :bentonite to #give herbicidal com-positions whichmay be appliedto living plants or to surfaces which are to be .freed irom plant growth. The ketones may also be mixed with liquid or solidag-ricultura-l pesticidese. g., insecticides and fungicides. While solutions of the ketones in organic solvents may be employed for-preventing andiiestreyin'g plant growth, we have found that the oil-in-water "emulsions possess an improved tendency -to *adhere to the treated surfaces and thatless'ofthe-active ingredients, i. e.,=-the ketones, is required to give comparable herbicidal efil- 'ciency.

What we claim 1. .Aherbicidal composition comprising .an oilin-water emulsion of a ketone having the formula 4 ketone, said ketone being present in said emulsion in a quantity which is toxic to plant life.

3. The method of destroying undesirable plants which comprises applying to said plants a toxic quantity of a herbicidal composition comprising a ketone having the formula COY in which R is selected from the class consisting :of hydrogen and alkyl radicals of from 1 to 5 carbon atoms and Y is an alkyl radical of from 1 to .5 carbon atoms, said ketone being present in :saiidcompositionina quantity which is toxic to plant life.

-.4. Theimethod of destroying undesirable plants which comprises applying to said plants a toxic quantity .of a. herbicidal composition comprising an oil-in-water emulsion o'ta ketone having the formula in which R is selected iromthe class consisting of hydrogen and alkyl radicals of from 1 to 5 carbon atoms, and Y is-an alkyl-radical of from 1 to 5 carbon atoms, said ketone being present in said emulsion in a quantity which is toxic to plantilife.

5. Themethod ofadestroyingundesirable:plants which comprises applying :to .said plants toxic quantity of a herbicidal composition comprising 3-thianaphthenyl methyl ketone.

.6. The methodbf destroying undesirable plants which comprises applying 'to said plants 2a toxic quantity IOf a herbicidal composition comprising an oil-iin-water emulsion 'of i3-thianaphthenyl methyl ketone.

7. The method of preventing .plant growth which comprises applying it!) media normally supporting said growth a herbicidal composition comprising .:a ketone having the formula in which Ris'selecte'd from "the class consisting of hydrogen and alkyl radicals of from 1 to "5 carbon atoms, and Yis an alkyl radicalof from 1 to 5 carbon atoms, said ,lketon'e being present in said emulsion in a :quantity which 'is'toxic to pl'ant'life.

Q. The "method or preventing plant growth which "comprises "applying to soil normally "sup-' porting said growth a herbicidal composition comprising a ketone having the formula in which R is selected from the class consisting of hydrogen and alkyl radicals of from 1 to 5 carbon atoms and Y is an alky1 radical of from 1 to 5 carbon atoms, said ketone being present in said composition in a quantity which is toxic to plant life.

10. The method of preventing plant growth which comprises applying to media normally 15 11. The method of preventing plant growth Which comprises applying to media normally supporting said growth an oil-in-water emulsion of 3-thianaphthenyl methyl ketone.

12. The method of preventing plant growth which comprises applying to soil normally supporting said growth a herbicidal composition comprising 3-thianaphthenyl methyl ketone.

13. The method of preventing plant growth which comprises applying to soil normally sup porting said growth an oil-in-water emulsion of 3-thianaphthenyl methyl ketone.

DAVID T. MOWRY. ARTHUR H. SCI-ILESHIGER.

No references cited. 

3. THE METHOD OF DESTROYING UNDESIRABLE PLANTS WHICH COMPRISES APPLYING TO SAID PLANTS A TOXIC QUANTITY OF A HERBICIDAL COMPOSITION COMPRISING A KETONE HAVING THE FORMULA 